Pros: Beautiful, non-agressive with people or birds, decent foragers
Cons: Terrible layers and uneconomical eaters. Not particularly friendly and fairly skittish.
Don't get me wrong - I really do like my Brahmas, but I don't love them.
Brahmas do very well in mixed flocks, in my experience are never bird-aggressive and can usually take up for themselves. They usually get along with EVERYONE in the flock but never seem to have any close friends.
It's neither a pro nor con to me - but they do go broody fairly often. My girls usually tried to brood about once a year but didn't drive us batty like the Cochins did. Also, they're weird. I don't know how to explain it any better than the fact we don't often call our Brahma by name, but instead elect to call her "Dur dur durr".
However, Brahmas are pretty bad layers of hysterically small eggs, and they'll eat you out of house and home. The one dark Brahma I have left probably eats more than the other 7 chickens in the coop combined.